In various applications, it is often beneficial to align two or more signals as closely in time as possible. For example, communication signals may have a relatively low average amplitude, but may contain crests that require higher than average power. FIG. 1 shows an example communication 100 signal (or, waveform); and FIG. 2 shows an amplitude of communication signal 100 having such crests 101. The amplitude of the signal is used as a proxy for its total instantaneous power requirements.
Referring to FIGS. 3 and 4, a fixed power supply providing constant power 104 that exceeds crests 101 results in considerable wasted power 105, making such a system inefficient. Accordingly, variable power supplies may be used to produce variable power that attempts to track the amplitude of the communication signal. For example, referring to FIG. 5, a variable power signal 106 may be generated by a variable power supply so that the power signal's envelope (e.g., the contours of the signal) tracks the envelope of the amplitude of communication signal 101. Misalignment between envelopes of signals 101 and 106, as shown in FIG. 6, can result in wasted power 107, leading to inefficiency.
Applications other than power management also benefit from alignment of two or more time-domain signals.